Question 958968
Sin theta= -12/13, theta lies in quadrant IV find cos theta/2
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working with (5-12-13) reference right triangle in quadrant IV
sinx=-12/13
cosx=5/13
{{{cos(x/2)=-sqrt((1+cosx)/2)=-sqrt(1+(5/13)/2)=-sqrt((18/13)/2)
=-sqrt(18/26)=-sqrt(9/13)=-3/sqrt(13)=-3sqrt(13)/13}}}